1. Field of the Invention
This invention relates to automatic washing machines of the vertical axis type.
2. Description of the Prior Art
In the agitation and scrubbing of clothing articles in a domestic washing machine, sediment and debris particles removed from the clothing articles generally have a density greater than the washing fluid and gravitate to the bottom of the washing basket, through the holes therein, and into the washing tub.
After the agitation cycle, the motor in the washing machine is reversed, causing the drain pump to begin to drain the basket and tub of washing liquid and at the same time causing the transmission to begin to drive the basket in rotation for the spin cycle. This is called a direct-into-spin system because the basket begins its spin cycle before the washing liquid has been drained therefrom.
Such a direct-into-spin system can cause a pressure gradient forcing the washing liquid from the tub through openings in the bottom of the basket and outwardly through the clothes, thus distributing sand and dirt particles that have settled within the tub on the clean clothes. This problem is described in U.S. Pat. No. 4,137,735 and proposed to be solved by moving a single row of openings in the bottom wall of the basket sufficiently far from the vertical axis of the agitator so that the pressure gradient will be too low to allow flow from the tub through the holes during the direct-into-spin cycle.
U.S. Pat. No. 3,246,837 discloses an annular channel connected beneath drip holes in the generally imperforate bottom basket to collect debris and distribute the debris centrifugally into the tub when the machine moves into the direct-into-spin portion of the cycle.
U.S. Pat. No. 2,900,812 discloses a sediment ring in the tub bottom, and a baffle covering a sector of the tub bottom to scour debris moved by vortex action during the agitation cycle toward the center of the tub bottom.